1. Technical Field
The present disclosure relates to switch circuits and, particularly, to a switch circuit for reducing fluctuation of the output voltage of the switch circuit.
2. Description of Related Art
In a switch circuit of an electronic device, a regulated capacitor is connected between an output of the switch circuit and ground to stabilize the output voltage of the switch circuit. FIG. 1 illustrates a known switch circuit 10, which includes a power switch transistor 11, a controlling circuit 12, and a regulated capacitor 13. The power switch transistor 11 is a n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) and connected between input 1 and output 2 of the switch circuit 10. A drain 4 of the power switch is connected to the input 1 of the switch circuit 10, a source 5 of the power switch is connected to the output 2 of the switch circuit 10, a gate (controlling electrode) 6 of the power switch transistor 11 is connected to output 3 of the controlling circuit 12. The controlling circuit 12 outputs pulse width modulation (PWM) signals to turn the power switch transistor 11 on and off and further to turn the switch circuit 10 on and off. The regulated capacitor 13 is connected between output 2 of the switch circuit 10 and ground to stabilize the output voltage of the switch circuit 10. However, at the moment when the power switch transistor 11 is turned on, the regulated capacitor 13 is charged first, thereby causing the output voltage of the switch circuit 10 to be less than the desired level.